Reducing agents for photographic processes

ABSTRACT

This invention relates to novel immobile reducing agents which, upon oxidation, auto-react intramolecularly in such a way as to form a new heterocyclic ring.

United States Patent Stanley M. Bloom Waban;

Paul S. l-luyifer, Lynnfield, both of Mass. 810,047

Sept. 16, 1968 Nov. 23, 1971 Polaroid Corporation Cambridge, Mass.

[72] Inventors [21 Appl. No. [22] Filed [45] Patented [73] AssigneeOriginal application July 24, 1967, Ser. No.

655,324, now Patent No. 3,482,971, dated Dec. 2, 1969. Divided and thisapplication Sept. 16, 1968, Ser. No. 810,047

[54] REDUCING AGENTS FOR PHOTOGRAPHIC PROCESSES 6 Claims, No Drawings[52] US. Cl 260/397.7, 260/347.2, 260/347.3, 260/347.4, ZOO/347.7,

R. 260/473 R, 260/556 A, 260/558 A, 260/559 R,

260/941, 260/944, 260/556 AR, 260/558 R Primary Examiner-J-lenry R.Jiles Assistant E.mminer-C. M. Shurko Atlorneys- Brown and Mikulka andAlvin lsaacs ABSTRACT: This invention relates to novel immobile reducingagents which, upon oxidation, auto-react intramolecularly in such a wayas to form a new heterocyclic ring.

REDUCING AGENTS FOR PHOTOGRAPHIC PROCESSES This application is adivision of copending US. Ser. No. 655,324, filed July 24, I967, now US.Pat. No. 3,482,971 patented Dec. 1969.

BACKGROLND OF THE INVENTION The copending application of Stanley M.Bloom and Howard G. Rogers Ser. No. 655,440, now U.S. Pat. No. 3,443,940patented May 13, l969, filed concurrently describes and claims certainphotographic procedures for forming positive color transfer imageswherein a photosensitive element containing at least one light-sensitivesilver halide emulsion and an associated layer of color providingmaterial is exposed and then developed with an aqueous alkalineprocessing composition including a silver halide solvent and a silverhalide developing agent. As a function of development, an imagewisedistribution of soluble silver complex is formed, and this imagewisedistribution migrates to the associated color-providing material whereit is reduced and the colorproviding material is in turn liberated fortransfer to a superposed stratum to impart thereto a positive colortransfer image.

In the practice of this photographic procedure, care must be taken toavoid a redox reaction between oxidized developing agent formed as afunction of development and the colorproviding material, since thisredox reaction interferes with the system upon which selective transferof color-providing material to the superposed stratum to form thedesired image is predicted.

One system for obviating this redox reaction is to incorporate in thephotosensitive element a reducing agent or scavenger" for the oxidizeddeveloper which will reduce the latter before it has had opportunity toreact with the colorproviding material. The scavenger" should ideallyprovide an immobile reaction product so that it will be unable tomigrate to the superposed stratum where it might adversely affect thecolor and/or stability of the desired color image.

SUMMARY The present invention is directed to a novel class of reducingagents which are of particular use in the aforementioned photographicprocesses and in procedures generally where it is desired that thereducing agent be immobile or nonmigratory. The reducing agents of thisinvention are also silver halide developing agents.

The novel reducing agents of this invention contain an immobilizing oranchoring" substituent which effectively precludes their migration andsubsequent competition with the color-providing material in theaforementioned photographic systems and further, upon oxidation, undergoa ringclosing reaction to form a new heterocyclic ring which alsocontributes to the immobility of the resulting compound Moreover, thisring-closure precludes any possibility of subsequent reduction which maybe undesirable in the photographic system described above.

As was mentioned previously, the present invention is directed to novelreducing agents.

A primary object of this invention, therefore, is to provide a novelclass of reducing agents.

Another object is to provide a novel class of reducing agents orscavengers of the foregoing description.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the product possessing the features,properties and the relation of components which are exemplified in thefollowing detailed disclosure, and the scope of the application of whichwill be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description.

The novel reducing agents of this invention may be represented by thefollowing formula:

benzene or naphthalene ring;

X is hydroxy or amino, e.g., a primary, secondary or tertiary aminosubstituent of the formula:

wherein each R may be hydrogen, a hydrocarbon radical, e.g., alkyl suchas methyl, ethyl, butyl, dodecyl, etc., aryl such as phenyl or naphthylattached through a carbon atom thereof to the nitrogen atom, a cyclicalkyl such as cyclopentyl or cyclohexyl, i.e., where both Rs arealkylene comprising together with a nitrogen atom a heterocyclic ring, asubstituted alkyl, such as hydroxyethyl, methoxyethoxyethyl,polyglycoloxyethyl, carboxymethyl, ethylcarboxymethyl, benzyl,phenylethyl, sulfo-phenylethyl, acetylamino-phenylethyl,succinylamino-phenylethyl, furanemethyl, etc.; or a substituted arylsuch as methylphenyl, ethylphenyl, etc; B is Y is a substantiallycolorless substituent, e.g., an aryl radical such as phenyl, naphthyl,or substituted derivatives thereof,

e.g., a nitro, alkyl or alkoxy-substituted phenyl or naphthyl, al-' kyl,alkoxy, hydroxyalkyl, haloalkyl, e.g., trifluoromethyl etc. wherein thealkyl moiety of the aforementioned substituents contains from one-l 8carbon atoms,

A and A each represent an anchoring or immobilizing substituentrendering the compound nondiffusible, e.g., higher alkyl such as decyl,dodecyl, stearyl, oleyl, etc. linked directly to the aromatic nucleus orlinked indirectly thereto through an appropriate linking group,

an aromatic ring, e.g., of the benzene or naphthalene series which ringsmay be either bonded to a single carbon atom of the aromatic nucleus orfused thereto, i.e., bonded to a pair of adjacent carbon atoms, or A andA each may be a plurality of short chain radicals which together providethe anchoring moiety, each of the short chain radicals being linkeddirectly or indirectly to a different carbon atom on the designatedaromatic nuclei;

and n and n are l or 2, provided that when X is a secondary or tertiaryamino comprising an anchoring moiety rendering said compoundnondiffusible, Y is a substituent providing an anchoring moiety, or Xand Y together provide an anchoring moiety, n and n may be 1, but when Xand Y alone or together do not provide such a substituent, at least oneof n and n must be 2; and nuclear substituted derivatives of thesecompounds, e.g., where any of the nuclear carbon atoms not containingone of the specifically designated substituents may contain an alkylsuch as methyl, ethyl, etc., alkoxy such as methoxy, ethoxy, etc.,carboxy, chloro or amide substituent.

The preferred class of compounds within formula A may be represented bythe following formula:

A (xi-l) I A (n 1) wherein X is hydroxy or primary amino and the othermoieties have the meanings heretofore noted; and nuclear sub- NH soQ-NO,

ll CH; CHr-CHr-CNHC12H26 5. NHz

ii Q-C-NH-CIBHU 5 i.

NH-S z 0121125 6. OH @Cuflu NH-SO Compound of Formula A It may bedesired for the X moiety to be in some other form during the abovecoupling reaction. For example, where X is hydroxy, it may be necessaryor advisable for it to be present as a protected derivative, e.g., analkoxy substituent, during coupling, in which event the desired hydroxyanalogue may subsequently be obtained by hydrolysis. Where X is primaryamino, it may be necessary or advisable to employ the correspondingl-nitro analogue in the coupling reaction, followed by reduction, e.g.,with hydrogen in the presence of a Raney nickel catalyst, to form thedesired amino compound.

The following examples show by way of illustration and not by way oflimitation the preparation of the novel compounds of this invention andtheir usefulness in the photographic processes described and claimed inthe aforementioned copending application, Ser. No. 655,440, now U.S.Pat. No. 3,443,940, patented May 13,1969.

EXAMPLE 1 l 1.0 g. (0.05mole) of fi-nitrodehydrocoumarin was dissolvedin 100.0 cc. of methyl cellosolve. 12.0 g. (0.064 mole) ofn-dodecylamine was then added. [The reaction was exothermic and a yellowsolid separated out.] The mixture was heated until a clear solution wasobtained and then cooled to give 14.0 g. oflight yellow crystals, m.p.168-170, an amido of the formula:

A mixture of 16.5 g. (0.0437 mole) of this amide, prepared in the mannerdescribed above, 7,0 g. (0.056 mole) of dimethylsulfate, 9.2 g. (0.066mole) of potassium carbonate and 250 ml. of xylene was refluxedovernight. The xylene was then removed by steam distillation and an oilyproduct crystallized on standing. Recrystallization of this product fromhexanechloroform yielded 13.3 g. of light tan needles, m.p. l06l08 C. ofthe formula:

OCH3

13.3 g. of this latter amide was hydrogenated in 95 percent ethanol inthe presence of Raney-Nickel catalyst. The reaction mixture was filteredand the filtrate evaporated. The resulting solid was recrystallized fromhexane-ether to obtain 9 g. of a pure white amine, m.p. 80-82 C. of theformula:

52 g. (0.145 mole) of the amine prepared in the above manner, 21.0 g.(0.145 mole) of 2-fluoronitrobenzene, 7.85 g. (0.195 mole) ofmagnesiumoxide and 100.0 ml. ofwater were heated in a sealed bomb at 180 C. for18 hours. The contents of the bomb were then filtered and the solidobtained by filtering was stirred in boiling ethyl acetate and filtered.Cooling of the filtrate yielded 40 g. ofa light yellow solid, m.p.125-l26 C.. of the formula:

I -01], curb-N (Ulhhr H 10.0 g. of the last-named product washydrogenated with 5 Pd/BaSO4 in ethyl acetate to reduce the nitro groupto the corresponding amine. The reaction mixture was filtered and thefiltrate was then cooled in dry ice. Filtration yielded 9 g. of anoff-white solid, m.p. 8 l -83 C. an amine of the formula:

OCH;

7 g. of the above sulfonamide in 50.0 cc. of dry dichloromethane wastreated with excess boron tribromide and allowed to stand overnight.Water was added to destroy the excess boron tribromide and the resultingsolid was filtered, stirred in boiling water and filtered again.Recrystallization from hexane-chloroform yielded 5.0 g. of the compoundofformula l a light tan solid, m.p. l39l41 C.

EXAMPLE 2 14.5 g. of p-methoxymethoxyaniline, 8.0 g. of 2-fluoro-4-stearamido-nitrobenzene, 4.0 g. of magnesium oxide and 100.0 ml. ofwater were heated with shaking at 180 C. for 2 days. After cooling, themixture was filtered to recover a solid which was recrystallized fromethyl acetate to yield 6.0 g. of an orange crystalline solid, m.p. l l8l19 C. of the formula:

OCHZOCH:

N |lI'(C 2)ioa 6.0 g. of this nitro compound was hydrogenated in ethylacetate using 5 percent palladium on barium sulfate as catalyst. Aftertheoretical hydrogen uptake was completed, the reaction mixture washeated to boiling and then filtered through celite. After cooling, thefiltrate was filtered to yield 4.0 g. of a white solid amine, m.p. ll3-l [4 C. of the formula:

OCHzOCHa NH-C-(CHghu-CH:

0 CHgO OH;

@NH-s o A mixture of 14.0 g. of the above compound, 50.0 ml. of ethanoland 2.0 ml. of concentrated HCI was heated under nitrogen on a steambath for 2 hours. The mixture was then stirred into ice water and theresulting solid was collected by filtration. After several dissolutionsin ethanol and precipitations from water, the resulting solid was driedto yield l 1.0 g. of the compound of formula 7, mp. 87-89 C.

EXAMPLE 3 A photosensitive element of the type disclosed in theaforementioned copending application Ser. No. (Case No. 3387), wasprepared by coating on a. cellulose acetate support a gelatin layercontaining a colloidal silver silver-precipitating agent andnondiffusible color-providing compound of the formula:

NH HO Water Hydroxyethyl cellulose 3.9 g. Sodium hydroxide 4.0 g. Sodiumthiosulfute 2.0 g. Sodium lulfite 2.0 g. Metul L6 After an imbibitiontime of about 2 minutes. the elements were separated to reveal apositive dye transfer image.

EXAMPLE 4 A similar photosensitive element containing no scavenger wasexposed and developed in the manner described in example 3. When theelements were separated following imbibition dye had transferred in bothexposed and unexposed areas so that no image formation was observable.

EXAMPLE 5 A photosensitive element may be prepared as in example 3.except that the compound of formula I may be included in the silverhalide emulsion layer at a calculated coverage of, for example, 68 mgm.per square foot. Such a photosensitive element may be exposed anddeveloped in the manner described in example 3 with a developingcomposition containing no silver halide developing agent, e.g., acomposition containing the following proportions of ingredients:

Water l00.0 cc. Hydroxyethyl cellulose 3.9 g. Sodium hydroxide 5.0 g.Sodium thiosull'ate l.0 g.

Employing a gap of 0.0016 inch, after 2 minutes the elements may beseparated to provide a positive dye image.

From the procedure illustrated in example 5, it will be observed thatthe compounds of this invention may be employed as silver halidedeveloping agents. While they are primarily intended for use in theprocesses described above. it will be apparent that they may find use assilver halide developing 5 agents in other photographic processes. e.g.,processes and claimed in' the aforementioned Ser. No. 655,440, now

US. Pat. No. 3,443,940, patented May 13, l969 wherein a photosensitiveelement including at least one light-sensitive silver halide emulsionhaving associated therewith a nondiffusible color-providing materialwhich is capable of providing an oxidation product which can auto-reactintramolecularly to effect ring-closure and to eliminate thecolor-providing moiety of said material for transfer is exposed and thendeveloped with an aqueous alkaline processing composition including asilver halide solvent and a silver halide developing agent the oxidationproduct of which is reducible by a redox reaction with thecolor-providing material, an imagewise distribution of soluble silvercomplex is formed in terms of unexposed areas of the emulsion; thenondiffusable color-providing material is contacted with the imagewisedistribution of silver complex where, in the presence ofsilver-precipitating nuclei, the complex is reduced and as a functionthereof an imagewise distribution of oxidized color-providing materialis'formed; the

oxidized material is allowed to auto-react intrarnolecularly toeliminate the color-providing moiety to provide an imagewisedistribution of diffusible color-providing moiety in terms of unexposedareas of the emulsion; and this imagewise distribution ofcolor-providing moiety is transferred, at least in part,

by imbibition to a superposed stratum to impart thereto a positive colortransfer image. In one procedure described in this copendingapplication, a scavenger for oxidized developer is positioned in a layerin the photosensitive element between the emulsion layer and the layerof color-providing material, so that oxidized developer formed as afunction of development is reduced before it can migrate to the layer ofcolorproviding material and there undergo an undesired redox reactionwith the color-providing material.

Since the novel compounds of this invention are effectively immobile intheir reduced form, they cannot migrate to the layer of color-providingmaterial where they would compete with the colohproviding material asreducing agents for the soluble silver complex, which competing would bedetrimental to proper image formation. Since these compounds are evenmore nonmigratory in their oxidized form, owing to ring-closure as afunction of oxidation, the oxidized form also cannot leave the layer inthe photosensitive element where they are employed and thereby adverselyaffect the quality and/or stability of the color transfer image.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involvedit isintended that all matter contained in the above description shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A compound ofthe formula:

said moiety is higher alkyl of from l2-l8 carbon atoms bonded to thearomatic nucleus through the group and Y is a colorless substituentselected from the group consisting of higher alkyls having from l2-l8carbon atoms,

phenyl, naphthyl or mono-hydroxy, mono-lower alkoxy, mono-lower alkyl.mono-nitro substituted derivatives of phenyl or naphthyl.

2. A compound of the formula ,wherein X is hydroxy or primary amino; Ais an anchoring moiety of high alkyl having from 12-18 carbon atomsconnected to the aromatic nucleus through and Y is a substantiallycolorless substituent chosen from the group consisting of phenyl,naphthyl, mono-hydroxy substituted derivatives of phenyl or naphthy ormono-nitro substituted derivatives of phenyl or naphthyl.

on g CH3- CHz-OHr-C-NHCrfiti NH @NH-SOz-Q 0 @cm-cm-d-micmm NH @NHSMQNLM

2. A compound of the formula